The present invention relates to cryogenic fluid flow control systems of the type comprising a first element forming a fluid inlet channel and an outlet passage that can be selectively blocked off by a second element that can move relative to the first element by an effect due to the difference in expansion coefficients between the materials of the first and second elements.
Known flow control systems of this type, such as those described for example in documents FR-A-2 377 588 or EP-A-0 170 948, comprise a needle that can move longitudinally relative to an outlet orifice due to the effect of axial differential expansions between the first element having the orifice and a moveable device that includes a rod and/or a bellows supporting the needle, in an arrangement that is tricky to manufacture and assemble, and therefore expensive and with no guarantee of reliability, especially in the presence of vibrations.
The object of the present invention is to propose a system of the type defined above that is of simple, robust and inexpensive construction and is of greater reliability.